Measurement of electrical properties of a biological sample, determination of physical properties of the biological sample from the measurement result, and discrimination of a kind of cell or the like included in the biological sample, and so on, are performed (for example, see Japanese Patent Application Laid-open No. 2009-042141). The measured electrical properties may be complex permittivity or frequency dispersion (a dielectric spectrum) thereof. The complex permittivity or the frequency dispersion is generally calculated by measuring a complex capacitance and complex impedance between electrodes using a solution retainer or the like including the electrodes configured to apply a voltage to a solution.
In addition, for example, in Japanese Patent Application Laid-open No. 2010-181400, a technology of obtaining information related to blood coagulation from permittivity of blood is disclosed, and “a blood coagulation system analysis device including a pair of electrodes, an application unit configured to apply an alternating current voltage to the pair of electrodes at predetermined time intervals, a measurement unit configured to measure the permittivity of the blood disposed between the pair of electrodes, and an analysis unit configured to analyze a level of function of the blood coagulation system using the permittivity of the blood measured at the time intervals after an action of the anticoagulant agent functioned in the blood is released” is disclosed.
When the electrical properties of the biological sample are measured, as a container configured to accommodate the biological sample, for example, Japanese Patent Application Laid-open No. 2012-052906 discloses a sample cartridge having a cylindrical body made of an insulating material, configured to hold the biological sample in a region including surfaces of electrodes inserted into an inner hole from both of end openings and a surface of the inner hole, and in which a constriction section disposed between the two opposite electrodes and formed by constricting the inner hole is installed at that region, measuring electrical properties of a biological sample.
Here, thus far, there has been known a problem that, when measuring an electrical property of a liquid biological sample containing sedimenting components, the sedimentation over time of sedimenting components influences the measurement result, and consequently the measurement accuracy is reduced.
For example, in the case where blood is selected as the biological sample and measurement is performed using the sample cartridge disclosed in Patent Literature 3, it is difficult to isolate the direct influence of the aggregation and coagulation process of blood and the influence of the change in blood sedimentation rate occurring in association with this. This is because the sample cartridge includes only a pair of electrodes for blood coagulation measurement and there is, depending on the disease, a strong correlation between blood coagulation and blood sedimentation rate, and therefore it is very difficult to assess whether the obtained measurement result reflects the degree of blood coagulation or reflects the sedimentation rate.
Further, also in the case where blood is selected as the biological sample and measurement is performed using a blood sedimentation meter, although the state of aggregation and coagulation of blood can be estimated from the change in blood sedimentation rate, only qualitative information is obtained because the accuracy is low because the estimation is an estimation dependent on a single model such as the Stokes equation or an empirical formula.